Longitudinal studies of sleep and wakefulness are essential for advancing basic knowledge of age-related sleep disorders. With the advent of modern microcomputers and algorithms for arousal state recognition, it is now possible to accurately and cost-effectively study age-related changes in sleep-wakefulness across the lifespan of individual animals. This Core Project proposal describes SCORE, an automated sleep-wake and physiological monitoring system that constitutes a major technological resource supporting all of the basic research components of this Program Project. SCORE was developed in our laboratory specifically for studies of sleep and circadian timekeeping in aging and has been implemented in a dedicated facility designed to support large multi-disciplinary research efforts. The large-scale implementation of the SCORE system permits real-time arousal state identification, body temperature measures, and detection of activity-dependent behaviors in 48 rodents simultaneously. These data are collected continuously 24 hours a day for weeks, months, or years at a time. Circadian rhythms in a variety of variables are monitored from another 80 animals, as well. Our SCORE system, dedicated facility, and highly trained staff who operate and manage the facility constitute an indispensable resource for the studies of circadian and homeostatic determinants of sleep and wakefulness in aging. The SCORE system and technical support group will provide cross-sectional and longitudinal sleep-wake, body temperature and behavioral data from animals that will be used in electrophysiology, neurochemistry, neuroanatomy, and molecular biology studies of age- related deterioration in circadian clock and sleep homeostatic function. The use of the SCORE system will permit unprecedented correlations between the data collected in vitro and in vivo assessments of the behavior and physiological status of individual animals with aging.